Practice
Pick a skill and keep going until it is automatic. Every problem has new numbers and a full worked solution. Your topics appear on the map below as you work.
Your progress
Unit 1: Exploring One-Variable Data and Collecting Data
- Topic 1.7Mean, median and standard deviationCompute the center and spread of a small data set, the way the exam expects you to with a calculator.
- Topic 1.7, 1.8Quartiles, IQR and outliersFind quartiles by the median-of-halves method and test for outliers with the 1.5 IQR rule.
- Topic 1.9, 2.11z-scores and relative positionStandardize a value, then compare positions in two different distributions.
Unit 2: Probability, Random Variables, and Probability Distributions
- Topic 1.9, 2.11z-scores and relative positionStandardize a value, then compare positions in two different distributions.
- Topic 2.2Relative frequencies from two-way tablesJoint, marginal and conditional relative frequencies, read from a table of counts.
- Topic 2.4, 2.5, 2.6, 2.7Probability from two-way tablesJoint, marginal and conditional probabilities read straight from a table of counts.
- Topic 2.4, 2.5, 2.6, 2.7Addition rule, complements and conditional probabilityCombine P(A), P(B) and P(A and B) correctly, and test whether two events are independent.
- Topic 2.8, 2.9Discrete random variables: mean and standard deviationFill in a missing probability, then find the expected value and the standard deviation.
- Topic 2.10Binomial probabilitiesExactly k, at most k and at least k successes, plus the mean and standard deviation of the count.
- Topic 2.11Normal distribution probabilitiesAreas to the left, to the right and between two values of a normal distribution.
- Topic 2.11Percentiles of a normal distributionWork backward from an area to the value that cuts it off.
Unit 3: Inference for Categorical Data: Proportions
- Topic 3.2Sampling distribution of a sample proportionCenter, spread and normal-approximation probabilities for p-hat.
- Topic 3.3, 3.4Confidence intervals for a proportionStandard error, margin of error and the interval itself, with the conditions checked.
- Topic 3.5, 3.6, 3.7Significance tests for a proportionTest statistic and p-value for a one-proportion z-test, and what they mean in context.
- Topic 3.4, 4.3Interpreting confidence intervals and levelsPick the interpretation that would earn credit on the exam, and see why the others would not.
- Topic 3.8Type I and Type II errorsName each error in context and see what moves the probability of each.
- Topic 3.10, 3.12, 3.13Comparing two proportionsThe difference in sample proportions, its standard error for an interval, the pooled proportion and the two-sample z statistic.
- Topic 3.14, 3.15Chi-square tests for two-way tablesExpected counts, the chi-square statistic, degrees of freedom and the p-value.
Unit 4: Inference for Quantitative Data: Means
- Topic 4.1Sampling distribution of a sample meanMean and standard deviation of x-bar, and the probability that a sample mean lands in a range.
- Topic 3.4, 4.3Interpreting confidence intervals and levelsPick the interpretation that would earn credit on the exam, and see why the others would not.
- Topic 4.2, 4.3Confidence intervals for a meanDegrees of freedom, t*, standard error and margin of error for a one-sample t interval.
- Topic 4.4, 4.5Significance tests for a meant statistic, degrees of freedom and p-value for a one-sample or paired t test.
- Topic 4.7, 4.9, 4.10Comparing two meansStandard error of a difference in means and the two-sample t statistic.
- Topic 4.9, 4.10Choose the inference procedureRead a study, then pick the interval or test that fits it. Three questions decide it every time.